Hydro-kinetic approach to relativistic heavy ion collisions

Journal Article · Mon Sep 15 04:00:00 EDT 2008 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.78.034906· OSTI ID:21192221

Akkelin, S V; Karpenko, Iu A; Sinyukov, Yu M ^[1]; Hama, Y ^[2]

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1. Bogolyubov Institute for Theoretical Physics, Metrolohichna str. 14b, 03680 Kiev-143 (Ukraine)
2. Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo, SP, C.P. 66318, 05315-970 (Brazil)

We develop a combined hydro-kinetic approach which incorporates a hydrodynamical expansion of the systems formed in A+A collisions and their dynamical decoupling described by escape probabilities. The method corresponds to a generalized relaxation time ({tau}{sub rel}) approximation for the Boltzmann equation applied to inhomogeneous expanding systems; at small {tau}{sub rel} it also allows one to catch the viscous effects in hadronic component-hadron-resonance gas. We demonstrate how the approximation of sudden freeze-out can be obtained within this dynamical picture of continuous emission and find that hypersurfaces, corresponding to a sharp freeze-out limit, are momentum dependent. The pion m{sub T} spectra are computed in the developed hydro-kinetic model, and compared with those obtained from ideal hydrodynamics with the Cooper-Frye isothermal prescription. Our results indicate that there does not exist a universal freeze-out temperature for pions with different momenta, and support an earlier decoupling of higher p{sub T} particles. By performing numerical simulations for various initial conditions and equations of state we identify several characteristic features of the bulk QCD matter evolution preferred in view of the current analysis of heavy ion collisions at RHIC energies.

• OSTI ID: 21192221
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 3 Vol. 78; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
APPROXIMATIONS
ATOM-ATOM COLLISIONS
BOLTZMANN EQUATION
BROOKHAVEN RHIC
COLLISIONS
DECOUPLING
EMISSION
EQUATIONS OF STATE
FREEZING OUT
HEAVY ION REACTIONS
HYDRODYNAMICS
PIONS
PROBABILITY
QUANTUM CHROMODYNAMICS
RELATIVISTIC RANGE
RELAXATION TIME
RESONANCE
SIMULATION
SPECTRA